Disturbances of melanin pigmentation are among the most conspicuous and common of dermatologic disorders seen in clinical practice. Although the majority of these lesions are benign, the possibility of malignant transformation in addition to cosmetic considerations, frequently necessitates their therapeutic removal. The laser will be appropriately designed and applied to selectively destroy only pigment cells while minimizing injury to surrounding structures, thus providing a less traumatic alternative with reduced scarring to surgical excision or dermabrasion. In Phase I, Candela Laser Corporation and Boston University School of Medicine established a set of laser and treatment parameters to restore normal pigmentation to patients with benign superficial pigmented lesions. In Phase II, we specifically aim to refine the treatment of superficial lesions by continuing clinical trials and developing a commercial prototype laser system. In addition, methods of treating deeper dermal lesions will be explored. To this end, the optical properties of pigmented lesions will be characterized using cells will be examined and a laser system embracing these results will be designed and tested in human clinical trials. Ultimately, a laser system which can treat both dermal and epidermal lesions will be produced.